1. Field of the Invention
The present invention relates to an image processing apparatus that performs predetermined processing for input image data, an image processing method, and a storage medium.
2. Description of the Related Art
There has conventionally been known a photographing method for blurring a background while focusing on a main object when photographing is carried out by a digital camera. This photographing method enables acquisition of an image of a dreamy effect by blurring a point light source to generate a circular bokeh in a portion corresponding to the point light source. Such a circular bokeh is generated by characteristics of a lens of the digital camera. The point light source is a region where there is local light of a certain size. Bokeh is a term of art commonly used to describe the aesthetic quality of a blur in out of focus areas of images.
There are known methods for fetching image data and processing it into an image where a circular bokeh has seemingly been generated (Japanese Patent Application Laid-Open Nos. 2009-003858 and 2009-218704).
Japanese Patent Application Laid-Open No. 2009-003858 discusses the method for changing a size or a shape of blurring when a light source region is blurred by selecting one of a plurality of filters prepared beforehand. Japanese Patent Application Laid-Open No. 2009-218704 discusses the method for emphasizing a high-luminance portion during background blur processing.
A circular bokeh region in an image actually captured by the digital camera varies with positions in an angle of view depending on optical characteristics of the lens. However, the methods discussed in Japanese Patent Application Laid-Open Nos. 2009-003858 and 2009-218704 perform uniform blur processing irrespective of positions in the image to be processed. In consequence, a blurred image that would be captured through the lens cannot be reproduced.